The objects of the present invention is to provide a preventive method for the progress of neuropsychiatric disorders, a therapeutic agent for neuropsychiatric disorders, a screening method thereof, and a therapeutic method through the analysis of the mechanisms leading to neuropsychiatric disorders such as Nasu-Hakola diseases and the like. The non-human animal model of oligodendrocytes developmental disorders was generated by making the DAP12 gene function deficient on its chromosome. The DAP12 knockout mouse develops myelination disorders including hypomyelinosis in the brain, particularly in the frontal head and the thalamus, further leading to neuropsychiatric disorders such as Nasu-Hakola disease and the like with aging. The screening method for a therapeutic agent, the diagnostic method, and the therapeutic method, wherein the DAP12 knockout mouse developing these disorders are used, have been developed